CAJ | 학술논문

采用真空再充 Ar 保护的 DSC 测量了Nd9 Fe85．5-x Cox B5．5(x＝3％,5％(原子分数))非晶薄带的升温曲线,计算了两种非晶薄带的晶化激活能E、频率因子Z、反应速率常数K、Avrami 指数n .实验证实了Co从3％(原子分数)增大到5％(原子分数)时晶化过程从一步改变为两步晶化；计算结果表明晶化起始温度T x 及晶化峰值温度T p 的晶化激活能、晶化反应速率常数均随Co的增加而增大,其主要原因是增大的频率因子起了关键作用；分析计算结果认为Nd9 Fe82．5 Co3 B5．5在升温速度10 K/min时局域Avrami指数n 随着晶化体积分数x 的增加先急剧降低而后缓慢降低、90％之后又有所升高,表明晶化形核在 x＜12％以三维形核方式为主,在x 为12％~36％时晶化以二维形核方式为主,之后直到晶化结束以一维形核方式为主.
채용진공재충 Ar 보호적 DSC 측량료Nd9 Fe85．5-x Cox B5．5(x＝3％,5％(원자분수))비정박대적승온곡선,계산료량충비정박대적정화격활능E、빈솔인자Z、반응속솔상수K、Avrami 지수n .실험증실료Co종3％(원자분수)증대도5％(원자분수)시정화과정종일보개변위량보정화；계산결과표명정화기시온도T x 급정화봉치온도T p 적정화격활능、정화반응속솔상수균수Co적증가이증대,기주요원인시증대적빈솔인자기료관건작용；분석계산결과인위Nd9 Fe82．5 Co3 B5．5재승온속도10 K/min시국역Avrami지수n 수착정화체적분수x 적증가선급극강저이후완만강저、90％지후우유소승고,표명정화형핵재 x＜12％이삼유형핵방식위주,재x 위12％~36％시정화이이유형핵방식위주,지후직도정화결속이일유형핵방식위주.
The heating curves of Nd9 Fe85 .5-x Cox B5 .5 (x=3%,5at%)amorphous alloy ribbons were measured by DSC protected by filling argon after vacuuming.The crystallization activation energy E,frequency factor Z,re-action rate constant K and Avrami exponent n of the two kinds of amorphous alloy ribbons were calculated ac-cording to the DSC curves.It was confirmed that the crystallization process changes from one step to two-steps with Co content increasing from 3% to 5at%.And the higher Co content in the alloy,the higher crystallization activation energy E and crystallization reaction rate constant K of both the initial crystallization temperature Tx and the peak one Tp.This was the reason that the increase of frequency factor Z playes a key role.At the heat-ing speed 10K/min,the local Avrami exponent n of Nd9 Fe82 .5 Co3 B5 .5 decreases sharply at first and then slow down with the increase of crystallization volume fraction x ,but it rises again when x was more than 90%.It demonstrates that when x was less than 12%,the crystallization nucleation mainly in the three-dimensional nu-cleation mode,and it changes into the two-dimensional nucleation one when x was 12%-36%,after 36% it does in the one-dimensional nucleation one.